Folding display frames are commonly used at trade shows for holding display panels assembled into a temporary display stand. Photomural displays and other graphics, projection screens, product display shelves, and the like are commonly mounted on the portable display stands.
Folding display frames typically comprise a number of rigid frame members pivotally connected together at their ends in a collapsible and portable form. The framework, in its expanded or open form, commonly consists of a grid of horizontal and vertical rod members forming an array of frame-like compartments or cubicles. The frame is carried to the exhibition hall in its collapsed form and is then erected to form the rigid structural framework for the display stand. Display panels which are mounted to the display frame, and other structural members of the supporting frame, also are carried to the trade show in a compact form. The entire folding display system is then assembled into the finished display unit. When the trade show is completed, the display frame is collapsed, and the display system is carried away in its portable form.
In a typical three-dimensional framework, a plurality of rod members are pivotally joined together to permit collapsing of the framework into a compact form in which the rod members lie substantially parallel to each other. Except where the framework is assembled in a substantially permanent structure, the rod members are pivotally joined at their ends to some type of hub, on which the rods can pivot relative to each other as the framework is adjusted between its open, expanded configuration and its closed compact storage configuration. An example of a foldable display frame that opens into an array of pivotally interconnected cubicles is disclosed in my U.S. Pat. No. 4,986,016, which is incorporated herein by this reference. In the display frame shown in that patent, the expanded display frame is collapsed by folding the pivotally joined rod members along two perpendicular axes until all rod members are substantially parallel to each other, with the hubs at the ends of the folded structure being nested closely to one another in a compact form.
One of the objectives in designing folding display frames is to make the structure light in weight and compact in its folded form to enhance ease of transportation and storage when the frame is not in use. At the same time, the framework, when fully expanded into its useful configuration, must be strong and fairly rigid. The framework not only must be strong enough to give adequate support to the display panels and the items mounted on them, but it also must withstand abuse, particularly when being constantly folded and unfolded.
The folding display frame shown in my U.S. Pat. No. 4,986,016 is useful in forming large main display frame structures which span a long side-to-side dimension of say ten to twenty feet and which also extend to a height of about eight to nine feet across the width of the main display frame. This display frame, comprising horizontal rows and vertical columns of interconnected cubicles, provides a stable supporting structure for large display stands.
In recent years, the display frame industry has seen a trend toward the development and use of more creative designs for display stands. This has resulted in use of display frames which are long and of narrow width, to be used as a column (pylon, post, pillar) or a bridge structure in the finished design. Most often these columns are used to support bridges or header frames which attach to other columns or to the main display frame with a span of about five to about sixteen to twenty feet. The column frame in these designs must be capable of handling vertical loads on one or two sides only without undue distortion or flexing.
Display frame columns have been made for many years of rigid, non-folding frameworks, generally of welded truss sections of steel rod and tubing. The frameworks sold under the mark "Interlock TransForm8" are an example. Display frame columns made of fixed truss sections fit into carrying cases only after the time-consuming effort of separating them into convenient lengths. The resulting parts are heavy, bulky, and quite expensive. Although they make a strong and attractive column, they do not contain means of attaching panels or art work in addition to the disadvantages of not being conveniently foldable.
It would be desirable to provide a column-like display frame in a conveniently foldable configuration. The previously known folding display frames, such as that shown in my U.S. Pat. No. 4,986,016, do not readily perform well in a column-like configuration. The preferred plan view size of a column is approximately ten or twelve inches square, whereas the plan view dimension of a single cubicle of a standard display frame is either eight or twelve inches in thickness but about twenty-eight to thirty-two inches in height and width. In order to have a small width, to form a column, it is possible to make many small cubicles so that a frame could be made with seven or ten hubs in height to produce a small cross-section. However, this arrangement makes a column that is otherwise of appropriate size too flexible in the left and right side directions. Additional bracing can be added, but the completed assembly would contain many more parts than a single cubicle of a standard display frame and is, therefore, too expensive to produce.
The objectives in designing a folding display frame, which can serve as a useful column structure, include the frame structure being collapsible into a small, transportable size; availability in various lengths to meet customer needs; light in weight while supporting heavy vertical loads, especially eccentric loading, without undue deflection or wobbling from side-to-side; avoiding use of too many structural parts which can make the resulting frame too expensive; resistance to deflection longitudinally, laterally and side-to-side, as well as resistance to torsion loads; and assembling and folding the column-like frame readily without interference of the structural parts or undue time required to connect or disconnect the frame members.
The present invention provides a collapsible display frame structure that can be expanded into a long and narrow column-shaped open frame in a structurally stable configuration. The display frame can be used as bridges, header frames, or act as a vertical column, and the frame is useful in a variety of lengths from about five to about twenty feet. The open frame column structure supports heavy loads and avoids undue deflection longitudinally, laterally, from side-to-side, and also resists torsion loads. It has a small number of parts that make the frame available at a reasonable cost, and the frame is light weight and readily collapsible to a small size. Other advantages are provided.